40:
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as operating the aircraft under visual flight rules (VFR), and is the most common mode of operation for small aircraft. However, it is safe to fly VFR only when these outside references can be clearly seen from a sufficient distance. When flying through or above clouds, or in fog, rain, dust or similar low-level weather conditions, these references can be obscured. Thus, cloud ceiling and flight visibility are the most important variables for safe operations during all phases of flight. The minimum weather conditions for ceiling and visibility for VFR flights are defined in FAR Part 91.155, and vary depending on the type of
164:) above the contiguous 48 United States and overlying the waters within 12 miles thereof. Flight in Class A airspace requires pilots and aircraft to be instrument equipped and rated and to be operating under instrument flight rules (IFR). In many countries commercial airliners and their pilots must operate under IFR as the majority of flights enter Class A airspace. Procedures and training are significantly more complex compared to VFR instruction, as a pilot must demonstrate competency in conducting an entire
265:, or through aircraft position reports in areas where radar coverage is not available. Aircraft position reports are sent as voice radio transmissions. In the United States, a flight operating under IFR is required to provide position reports unless ATC advises a pilot that the plane is in radar contact. The pilot must resume position reports after ATC advises that radar contact has been lost, or that radar services are terminated.
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many countries is "Special VFR" flight, where an aircraft is explicitly granted permission to operate VFR within the controlled airspace of an airport in conditions technically less than VMC; the pilot asserts they have the necessary visibility to fly despite the weather, must stay in contact with ATC, and cannot leave controlled airspace while still below VMC minimums.
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160:(IMC), which is essentially any weather condition less than VMC but in which aircraft can still operate safely. Use of instrument flight rules is also required when flying in "Class A" airspace regardless of weather conditions. Class A airspace extends from 18,000 feet above mean sea level to flight level 600 (60,000 feet
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crashes. VFR flight into IMC is distinct from "VFR-on-top", an IFR procedure in which the aircraft operates in VMC using a hybrid of VFR and IFR rules, and "VFR over the top", a VFR procedure in which the aircraft takes off and lands in VMC but flies above an intervening area of IMC. Also possible in
307:
It is essential to differentiate between flight plan type (VFR or IFR) and weather conditions (VMC or IMC). While current and forecast weather may be a factor in deciding which type of flight plan to file, weather conditions themselves do not affect one's filed flight plan. For example, an IFR flight
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It is possible and fairly straightforward, in relatively clear weather conditions, to fly an aircraft solely by reference to outside visual cues, such as the horizon to maintain orientation, nearby buildings and terrain features for navigation, and other aircraft to maintain separation. This is known
364:
for aircraft landing on the same runway surface, but from opposite directions. Aircraft approaching from the north must make visual contact with the airport at a higher altitude than when approaching from the south because of rapidly rising terrain south of the airport. This higher altitude allows a
513:
In the UK, an IR (UK restricted) - formerly the "IMC rating" - which permits flight under IFR in airspace classes B to G in instrument meteorological conditions, a non-instrument-rated pilot can also elect to fly under IFR in visual meteorological conditions outside controlled airspace. Compared to
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system. Air traffic control may assist in navigation by assigning pilots specific headings ("radar vectors"). The majority of IFR navigation is given by ground- and satellite-based systems, while radar vectors are usually reserved by ATC for sequencing aircraft for a busy approach or transitioning
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During flight under IFR, there are no visibility requirements, so flying through clouds (or other conditions where there is zero visibility outside the aircraft) is legal and safe. However, there are still minimum weather conditions that must be present in order for the aircraft to take off or to
338:
It is important not to confuse IFR with IMC. A significant amount of IFR flying is conducted in visual meteorological conditions (VMC). Anytime a flight is operating in VMC and in a volume of airspace in which VFR traffic can operate, the crew is responsible for seeing and avoiding VFR traffic;
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In uncontrolled airspace, ATC clearances are unavailable. In some states a form of separation is provided to certain aircraft in uncontrolled airspace as far as is practical (often known under ICAO as an advisory service in class G airspace), but separation is not mandated nor widely provided.
146:
Visual flight rules are generally simpler than instrument flight rules, and require significantly less training and practice. VFR provides a great degree of freedom, allowing pilots to go where they want, when they want, and allows them a much wider latitude in determining how they get there.
494:. Flight under IFR beyond six months after meeting these requirements is not permitted; however, currency may be reestablished within the next six months by completing the requirements above. Beyond the twelfth month, examination ("instrument proficiency check") by an instructor is required.
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Specific procedures allow IFR aircraft to transition safely through every stage of flight. These procedures specify how an IFR pilot should respond, even in the event of a complete radio failure, and loss of communications with ATC, including the expected aircraft course and altitude.
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routing, where only the destination, or a few navigational waypoints are used to describe the route that the flight will follow. ATC will assign altitudes in its initial clearance or amendments thereto, and navigational charts indicate minimum safe altitudes for airways.
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land; these vary according to the kind of operation, the type of navigation aids available, the location and height of terrain and obstructions in the vicinity of the airport, equipment on the aircraft, and the qualifications of the crew. For example,
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Departures are described in an IFR clearance issued by ATC prior to takeoff. The departure clearance may contain an assigned heading, one or more waypoints, and an initial altitude to fly. The clearance can also specify a departure procedure (DP) or
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use cockpit instruments as secondary aids to navigation and orientation, but are not required to; the view outside of the aircraft is the primary source for keeping the aircraft straight and level (orientation), flying to the intended destination
342:
Although dangerous and illegal, a certain amount of VFR flying is conducted in IMC. A scenario is a VFR pilot taking off in VMC conditions, but encountering deteriorating visibility while en route. Continued VFR flight into IMC can lead to
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however, because the flight is conducted under instrument flight rules, ATC still provides separation services from other IFR traffic, and can in many cases also advise the crew of the location of VFR traffic near the flight path.
509:
is required so that the pilot practicing instrument approaches can wear a view-limiting device which restricts his field of view to the instrument panel. A safety pilot's primary duty is to observe and avoid other traffic.
81:
defines IFR as: "Rules and regulations established by the FAA to govern flight under conditions in which flight by outside visual reference is not safe. IFR flight depends upon flying by reference to instruments in the
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The aircraft must be equipped and type-certified for instrument flight, and the related navigational equipment must have been inspected or tested within a specific period of time prior to the instrument flight.
276:, which is the farthest the aircraft can fly without a new clearance. In addition, a clearance typically provides a heading or route to follow, altitude, and communication parameters, such as frequencies and
312:(VMC) en route does not automatically change to a VFR flight, and the flight must still follow all IFR procedures regardless of weather conditions. In the US, weather conditions are forecast broadly as VFR,
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When operation of an aircraft under VFR is not safe, because the visual cues outside the aircraft are obscured by weather, instrument flight rules must be used instead. IFR permits an aircraft to operate in
126:
of flight visibility and a distance from clouds of 500 feet below, 1,000 feet above, and 2,000 feet horizontally. Flight conditions reported as equal to or greater than these VFR minimums are referred to as
883:
574:. From 1999 single-engine helicopters could not be FAA-certified for IFR. Recently, however, Bell and Leonardo have certified the single engine helicopters for instrument flight rules.
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Instrument pilots must carefully evaluate weather, create a detailed flight plan based around specific instrument departure, en route, and arrival procedures, and dispatch the flight.
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Any aircraft operating under VFR must have the required equipment on board, as described in FAR Part 91.205 (which includes some instruments necessary for IFR flight). VFR pilots
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482:(meet recency of experience requirements). In the United States, to file and fly under IFR, a pilot must be instrument-rated and, within the preceding six months, have flown six
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the rest of the world, the UK's flight crew licensing regime is somewhat unusual in its licensing for meteorological conditions and airspace, rather than flight rules.
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flight crew to clear the obstacle if a landing is aborted. In general, each specific instrument approach specifies the minimum weather conditions to permit landing.
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in which the aircraft is operating, and on whether the flight is conducted during daytime or nighttime. However, typical daytime VFR minimums for most airspace is 3
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Because IFR flights often take place without visual reference to the ground, a means of navigation other than looking outside the window is required. A number of
39:
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Despite the protection offered by flight in controlled airspace under IFR, the ultimate responsibility for the safety of the aircraft rests with the
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372:(TAWS), these are primarily backup systems providing a last layer of defense if a sequence of errors or omissions causes a dangerous situation.
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commences. An instrument approach terminates either by the pilot acquiring sufficient visual reference to proceed to the runway, or with a
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715:
Keel, Byron; Stancil, Charles; Eckert, Clifford; Brown, Susan (June 2000). "Aviation
Weather Information Requirements Recommendations".
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In the United States, instruments required for IFR flight in addition to those that are required for VFR flight are:
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249:. The most important concept of IFR flying is that separation is maintained regardless of weather conditions. In
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331:(VMC). To operate safely in IMC ("actual instrument conditions"), a pilot controls the aircraft relying on
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428:(SID) that should be followed unless "NO DP" is specified in the notes section of the filed flight plan.
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En route flight is described by IFR charts showing navigation aids, fixes, and standard routes called
327:(IMC). The weather is considered to be MVFR or IMC when it does not meet the minimum requirements for
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86:, and navigation is accomplished by reference to electronic signals." It is also a term used by
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704:, Oklahoma City, Oklahoma: Federal Aviation Administration, 11 February 2010, pp. PCG I−4
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based on route, time, distance, speed, and altitude. ATC monitors IFR flights on
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The distance by which an aircraft avoids obstacles or other aircraft is termed
683:, Oklahoma City, Oklahoma: Federal Aviation Administration, 2008, pp. G–9
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Although large airliners, and increasingly, smaller aircraft, carry their own
257:(ATC) separates IFR aircraft from obstacles and other aircraft using a flight
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was created from a revision of this article dated 9 December 2017
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719:. Hampton, Virginia: NASA Langley Research Center. pp. 40–41.
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ATC Communication, A complete pilot-to-ATC communication reference
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Federal
Aviation Regulations Title 14, Chapter I, Subchapter E,
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are available to pilots, including ground-based systems such as
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for "LOC RWY 16R", "ILS RWY 16R", and "ILS or LOC/DME RWY 34L".
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The main purpose of IFR is the safe operation of aircraft in
62:) is one of two sets of regulations governing all aspects of
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for each part of the flight. A clearance always specifies a
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Practicing instrument approaches can be done either in the
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because the required visual reference is not seen in time.
360:(KRNO) in a mountainous region has significantly different
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of the pilot which is the cause of a significant number of
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an aircraft is flying, such as an IFR or VFR flight plan.
449:(STAR), describing common routes to fly to arrive at an
1106:
Hear audio of a US instrument rating checkride - Part 1
1028:
US Code of
Federal Regulations, 14 CFR 61.57(c) and (d)
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The approach portion of an IFR flight may begin with a
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761:"14 CFR 91.155 [ Basic VFR weather minimums ]"
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procedures and course interception and tracking with
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aircraft from takeoff to cruise, among other things.
790:"FAR Part 91 Sec. 91.205 effective as of 10/20/2009"
27:
Civil aviation regulations for flight on instruments
958:
Aviation
Weather Center - METARs Help Page (4 of 5)
542:with a sweep-second pointer or digital equivalent,
143:, and avoiding obstacles and hazards (separation).
960:National Weather Center. Retrieved 29 January 2015
268:IFR flights in controlled airspace require an ATC
1012:
1010:
717:Aviation Weather Information Requirements Study
320:), IFR, or LIFR (low instrument flight rules).
1151:
1111:"Blind Flying, January 1933, Popular Mechanics
8:
1017:"Terrain Awareness and Warning Systems—TAWS"
1068:"Resurrecting single-engine helicopter IFR"
812:
810:
213:. Unsourced material may be challenged and
32:"IFR" redirects here. For other uses, see
724:
233:Learn how and when to remove this message
1168:, and does not reflect subsequent edits.
566:rate-of-turn indicator that is either a
665:
474:To fly under IFR, a pilot must have an
742:
732:
589:Acronyms and abbreviations in avionics
817:Collins, Richard (11 November 2006).
7:
1113:details on blind flying for that era
499:instrument meteorological conditions
370:terrain awareness and warning system
325:instrument meteorological conditions
211:adding citations to reliable sources
168:solely by reference to instruments.
158:instrument meteorological conditions
1066:Hirschberg, Mike (April–May 2015).
927:"IFR Flight Prep: A Whole New Game"
1019:. Skybrary. Retrieved 11 July 2014
66:aircraft operations; the other is
25:
852:"The Basics: VFR Flight Planning"
702:Instrument Flight Rules (defined)
695:"Aeronautical Information Manual"
681:Instrument Flight Rules (defined)
107:Comparison to visual flight rules
43:IFR in between cloud layers in a
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503:visual meteorological conditions
358:Reno-Tahoe International Airport
329:visual meteorological conditions
310:visual meteorological conditions
183:
129:visual meteorological conditions
925:Goyer, Robert (30 April 2010).
447:standard terminal arrival route
396:as well as the satellite-based
75:Federal Aviation Administration
819:"Getting an Instrument Rating"
1:
426:standard instrument departure
335:and ATC provides separation.
291:, who can refuse clearances.
850:Wallace, Lane (3 May 2010).
768:Federal Aviation Regulations
674:"Instrument Flying Handbook"
624:Distance measuring equipment
318:marginal visual flight rules
303:IFR flying with clouds below
770:: 721–722. 11 February 2010
554:for the route to be flown,
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649:Transponder landing system
584:Index of aviation articles
408:
110:
79:Instrument Flying Handbook
31:
654:VHF omnidirectional range
639:Instrument landing system
884:"FAR Part 71 Sec. 71.33"
505:– in the latter case, a
175:Separation and clearance
94:to indicate the type of
572:turn and bank indicator
151:Instrument flight rules
56:instrument flight rules
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1126:Listen to this article
644:Non-directional beacon
345:spatial disorientation
304:
47:
1145:
972:"Safety Pilot in IMC"
484:instrument approaches
362:instrument approaches
302:
42:
1198:Aviation meteorology
1177:More spoken articles
453:(IAF) from which an
451:initial approach fix
207:improve this section
166:cross-country flight
34:IFR (disambiguation)
982:on 5 September 2007
890:on 23 February 2017
536:barometric pressure
532:sensitive altimeter
455:instrument approach
411:Instrument approach
255:air traffic control
251:controlled airspace
113:Visual flight rules
68:visual flight rules
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629:Flight instruments
594:Aeronautical chart
544:attitude indicator
333:flight instruments
305:
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1072:Vertical Magazine
528:heading indicator
476:instrument rating
382:navigational aids
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162:pressure altitude
102:Basic information
18:Instrument flight
16:(Redirected from
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1078:on 19 April 2015
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1193:Aviation law
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1080:. Retrieved
1076:the original
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1049:. Retrieved
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1024:
996:
984:. Retrieved
980:the original
976:IFR magazine
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941:. Retrieved
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892:. Retrieved
888:the original
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866:. Retrieved
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833:. Retrieved
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772:. Retrieved
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619:Bárány chair
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507:safety pilot
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141:(navigation)
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1101:FAA website
943:27 November
868:27 November
835:27 November
794:rgl.faa.gov
774:27 November
743:|work=
634:Helmet fire
278:transponder
96:flight plan
92:controllers
84:flight deck
1187:Categories
1173:Audio help
1164:2017-12-09
660:References
564:gyroscopic
556:alternator
405:Procedures
376:Navigation
247:separation
45:Cessna 172
1000:See KRNO
894:24 August
745:ignored (
735:cite book
721:CiteSeerX
614:Autopilot
560:generator
439:direct-to
270:clearance
259:clearance
194:does not
77:'s (FAA)
73:The U.S.
1203:Avionics
1175: ·
1082:11 April
1051:31 March
831:(11): 68
799:31 March
609:Autoland
578:See also
552:avionics
518:Aircraft
398:GPS/GNSS
120:airspace
52:aviation
1162: (
1133:minutes
1046:gpo.gov
939:(4): 56
864:(4): 61
570:or the
492:navaids
488:holding
480:current
434:airways
295:Weather
280:codes.
215:removed
200:sources
131:(VMC).
70:(VFR).
986:20 May
932:Flying
914:§71.33
910:§71.31
857:Flying
824:Flying
723:
548:radios
501:or in
88:pilots
1042:(PDF)
764:(PDF)
698:(PDF)
677:(PDF)
540:clock
470:Pilot
263:radar
1084:2015
1053:2018
988:2009
945:2010
896:2015
870:2010
837:2010
801:2018
776:2010
747:help
413:and
394:NDBs
392:and
390:VORs
314:MVFR
198:any
196:cite
90:and
937:137
862:137
829:133
558:or
386:DME
209:by
136:may
60:IFR
50:In
1189::
1131:20
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737:}}
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